3 Oil and Gas Shares That Plunged This Week

LONDON -- This week has seen strong gains in the price of oil, helped by temporary production shortfalls from key North Sea fields, several of which are undergoing maintenance during the brief summer season.

As a result, September Brent Crude has risen from around $108.50 at the start of the week to finish at more than $112, having peaked at over $113 per barrel on Thursday. U.S. benchmark WTI Crude has also risen, from $88 per barrel at the start of the week to just over $92 when U.S. markets opened on Friday.

Natural gas prices have remained weaker but were given some support by reduced inventories in U.S. markets and look set to end the week slightly higher. As a result, investors in the United States Oil Fund (NYS: USO) have seen their holdings rise in value by 1.4%, while the United States Natural Gas Fund (NYS: UNG) was 1.5% lower on the week when markets opened on Friday.

However, a rising oil price has not been enough to protect the share prices of some small oil and gas companies, whose share prices fell against the market this week. Here are the three of this week's worst performers from the U.K. and U.S. markets:

Advantage Oil & Gas Ltd. (NYS: AAV) Advantage Oil & Gas had dropped 14.5% to $3.33 by the time U.S. markets opened on Friday. The slide followed quarterly results that showed a big fall in income over the last three months, thanks to reduced liquids production and a dramatic drop in achieved gas prices, which had previously been hedged at much higher levels.

Bahamas Petroleum (ISE: BPC.L) Bahamas Petroleum reversed gains from earlier in the week and was down more than 5% on Friday alone, at 7.2 pence. The company has not issued any formal updates since April, when it responded to suggestions that it had not fulfilled the terms of its licenses in the Bahamas and might be in danger of having them taken away by the country's new government.

Borders & Southern Petroleum (ISE: BOR.L) Borders & Southern slipped just 1.4% to 17.3 pence this week, but it remains an awful performer of the last 30 days, having lost 74% of its market value since mid-July. Borders' failure to find oil or substantial amounts of gas in its Darwin and Stebbing wells in the South Atlantic could be the final straw for the explorer -- but its Darwin gas find could yet be proved commercial, especially if neighboring explorer Falkland Oil & Gas finds some, too.

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